water biology

Question 1

Describe bonding in water

Answer 1

Hydrogen Bonding between molecules this is called intermolecular bonding
covalent bonding between the O and H, this is called intramolecular bonding
- Intramolecular is always stronger than intermolecular

Question 2

describe how hydrogen bonding happens

Answer 2

• Hydrogen bonding happens because the water is polar and has a slight charge, the oxygen attracts more electrons making it negative whereas the hydrogen has a more positive charge.
• opposites attract and create an intermolecular bond

Question 3

list properties of water

Answer 3

• high specific heat capacity
• high latent heat of evaporation
• cohesive
• solvent
• ice
• metabolism
• liquid

Question 4

Describe specific heat capacity as a property of water

Answer 4

Hydrogen bonds between water, these can absorb the energy making it very hard for the bonds to break therefore there is a high specific heat capacity.
increasing the temperature increases the kinetic energy, a lot of energy is required to increase the kinetic energy and break the hydrogen bonds
- hydrogen bonds are stable

Question 5

why is high specific heat capacity of water good for organisms

Answer 5

• living things include prokaryotes and eukaryotes need a stable temperature for enzyme controlled reactions to happen properly
• aquatic organisms need a stable environment in which to live

Question 6

Describe high latent heat of vaporisation (properties of water)

Answer 6

• hydrogen bonds are stable and require a lot of energy to break
• the latent heat of evaporation is the energy required to get water from one state to another, this means a lot of energy is required to break the hydrogen bonds allowing it to change.

Question 7

Why is high latent heat of vaporisation of water food for organisms

Answer 7

help keep cool living things and keep their temperature stable
- sweating and plants cool when the water evaporates from mesophyll cells

Question 8

Describe cohesion and surface area tension - properties of water

Answer 8

• cohesion tension theory
• water molecules attract to each other because of their hydrogen bonds and create long columns of water
• help water to glow as they stick together so pull one another along
• good for transport medium and liquid as it flows
• water molecules on the surface are all hydrogen bonded to the molecules beneath them and hence more attracted to the water molecules beneath than the air above, therefore the water contracts and this gives the surface of the water an ability to resit the force applied to it, this is known as surface tension

Question 9

why is cohesion and surface area tension good for water molecules

Answer 9

Columns of water in plant vascular tissue are pulled up by the xylem tissue together from the roots
insects can walk on water for example pond skaters

Question 10

Describe ice - properties of water

Answer 10

• forms ice
• hydrogen bonds spread the water molecules out and creates a lattice structure making the water less dense in a solid state than in a liquid state, this causes it to float and form a layer.
• creates an insulating layer meaning organisms underneath do not freeze and can stay alive
• can survive in a cold environment as water underneath does not survive

Question 11

Describe metabolism - properties of water

Answer 11

reactant - hydrolysis and photosynthesis
product - condensation and respiration
- important for the digestion and synthesis of large biological molecules